Quantum simulation of particle pair creation near the event horizon

Though it is still a big challenge to unify general relativity and quantum mechanics in modern physics, the theory of quantum field related with the gravitational effect has been well developed and some striking phenomena are predicted, such as Hawking radiation. However, the direct measurement of these quantum effects under general relativity is far beyond present experiment techniques. Fortunately, the emulation of general relativity phenomena in the laboratory has become accessible in recent years. However, up to now, these simulations are limited either in classical regime or in flat space whereas quantum simulation related with general relativity is rarely involved. Here we propose and experimentally demonstrate a quantum evolution of fermions in close proximity to an artificial black hole on a photonic chip. We successfully observe the acceleration behavior, quantum creation, and evolution of a fermion pair near the event horizon: a single-photon wave packet with positive energy escapes from the black hole while negative energy is captured. Our extensible platform not only provides a route to access quantum effects related with general relativity, but also has the potentiality to investigate quantum gravity in future.     

A review of ontology based query expansion

This paper examines the meaning of context in relation to ontology based query expansion and contains a review of query expansion approaches. The various query expansion approaches include relevance feedback, corpus dependent knowledge models and corpus independent knowledge models. Case studies detailing query expansion using domain-specific and domain-independent ontologies are also included. The penultimate section attempts to synthesise the information obtained from the review and provide success factors in using an ontology for query expansion. Finally the area of further research in applying context from an ontology to query expansion within a newswire domain is described.     

FCA based ontology development for data integration

Data is a valuable asset to our society. Effective use of data can enhance productivity of business and create economic benefit to customers. However with data growing at unprecedented rates, organisations are struggling to take full advantage of available data. One main reason for this is that data is usually originated from disparate sources. This can result in data heterogeneity, and prevent data from being digested easily. Among other techniques developed, ontology based approaches is one promising method for overcoming heterogeneity and improving data interoperability. This paper contributes a formal and semi-automated approach for ontology development based on Formal Concept Analysis (FCA), with the aim to integrate data that exhibits implicit and ambiguous information. A case study has been carried out on several non-trivial industrial datasets, and our experimental results demonstrate that proposed method offers an effective mechanism that enables organisations to interrogate and curate heterogeneous data, and to create the knowledge that meets the need of business.     

A particle inerter system for structural seismic response mitigation

This study introduces a novel particle inerter system (PIS) designed for vibration mitigation of structures. The new system comprises an inerter subsystem, a spring, and a tuned particle element, where the spring is used for tuning the particle element and the inerter subsystem is set for energy absorption and dissipation. The structural performance and the vibration mitigation effect of the PIS are assessed in terms of displacement and acceleration responses. An optimal design method is developed for a PIS under a performance-oriented design framework. Following the criterion of lightweight control, the added mass of the PIS is minimized under the constraints of target displacement and acceleration responses. A parametric analysis is performed and the robustness of the PIS for seismic response mitigation is verified. Design cases are carried out for the illustration of the proposed design method. The results show that the structural displacement and acceleration responses can be reduced significantly with the help of a PIS. Compared with the particle tuned mass damper with the same parameters, both the energy absorption and dissipation effects of the PIS are increased and the relative displacement response of the container in the PIS is reduced by the inerter subsystem. Under the same performance target, the required physical mass of the container and particles in the PIS is minimized and is significantly smaller than that of the conventional particle tuned mass damper.     

Incorporating compactness to generate term-association view snippets for ontology search

A query-relevant snippet for ontology search is useful for deciding if an ontology fits users’ needs. In this paper, we illustrate a good snippet in a keyword-based ontology search engine should be with term-association view and compact, and propose an approach to generate it. To obtain term-association view snippets, a model of term association graph for ontology is proposed, and a concept of maximal r-radius subgraph is introduced to decompose the term association graph into connected subgraphs, which preserve close relations between terms. To achieve compactness, in a query-relevant maximal r-radius subgraph, a connected subgraph thereof with a small graph weight is extracted as a sub-snippet. Finally, a greedy method is used to select sub-snippets to form a snippet in consideration of query relevance and compactness without violating the length constraint. An empirical study on our implementation shows that our approach is feasible. An evaluation on effectiveness shows that the term-association view snippet is favored by users, and the compactness helps reading and judgment.     

A general modulation theory for single-phase Thyristor systems

Amplitude Modulation (AM) and Phase Modulation (PM) processes of discrete form have been discussed in a previous associated paper. This present paper discusses discrete Frequency Modulation (FM) in power frequency circuits, highlighting their advantages compared with amplitude and phase modulations. Mixed modulation systems of both PM and FM nature are introduced to solve the disadvantages and undesirable features associated with pure FM modulation. A generalised equation of modulation is introduced to represent the various forms of power frequency modulation.     

Enhancing relevant concepts extraction for ontology learning using domain time relevance

Concepts extraction is the backbone task for an ontology construction system. Identifying the relevant concepts is considered one of the main challenges of automatic ontology construction (called Ontology Learning (OL)). This research introduces a novel relevance metric that estimates the sustainability distribution of concepts to identify the modern and relevant concepts, called Domain Time Relevance (DTR). Also, this research proposes a Developed Concepts extraction Model based on the proposed DTR, namely DTR-DCEM. This proposed model uses the proposed Concepts extraction stopwords (CE-stopwords) list to avoid noise data. This proposed model, DTR-DCEM, aims to extract the relevant concepts from scientific publications. The experiments are conducted in two different datasets: DL2019 and ACLRelAcS. The experimental results show that the proposed model DTR-DCEM outperforms the state-of-the-art models. It got between (3.32～51.07)% better performance than comparative models for the DL2019 dataset and between (3.29～24.51)% better performance for the ACLRelAcS dataset. Moreover, the statistical significance of the proposed model DTR-DCEM has been proved using paired t-test.     

A scalable fish-school inspired self-assembled particle system for solar-powered water-solute separation

Complete separation of water and solute is the ultimate goal of water treatment, for maximized resource recycling. However, commercialized approaches such as evaporative crystallizers consume a large amount of electricity with a significant carbon footprint, leading to calls for alternative energy-efficient and eco-friendly strategies. Here, inspired by schooling fish, we demonstrate a collective system self-assembled by expanded polystyrene (EPS)-core/graphene oxide (GO)-shell particles, which enables autonomous, efficient and complete water-solute separation powered by sunlight. By taking advantage of surface tension, these tailored particles school together naturally and are bonded as a system to function collectively and coordinatively, to nucleate, grow and output salt crystals continuously and automatically out of even saturated brine, to complete water-solute separation. Solar-vapor conversion efficiency over 90% and salt production rate as high as 0.39 kg m^–2 h^–1 are achieved under 1-sun illumination for this system. It reduces the carbon footprint of ∼50 kg for treating 1-ton saturated brine compared with the commercialized approaches.     

基于场论的创新产品扩散扰动模型研究

 运用物理学中场的思想和Logistic基本原理构建了创新产品扩散扰动模型,并用该模型对中国移动通信产品扩散扰动进行了实证分析。结果表明,提高企业市场占有量的决定性因素不是自然扩散率,而是其外部竞争力,即扩散的外部扰动作用。     

Determinate Values for Quantum Observables

This is a comment on J. A. Barrett's article ‘The Preferred-BasisProblem and the Quantum Mechanics of Everything’ ([2005]),which concerns theories postulating that certain quantum observableshave determinate values, corresponding to additional (oftencalled ‘hidden’) variables. I point out that itis far from clear, for most observables, what such a postulateis supposed to mean, unless the postulated additional variableis related to a clear ontology in space-time, such as particleworld lines, string world sheets, or fields.